229
FXUS65 KBYZ 241221
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
621 AM MDT THU SEP 24 2026
KEY MESSAGES
- WARM AND DRY END OF THE WORK WEEK AND START TO THE WEEKEND.
- UNSETTLED AND COOLER SUNDAY INTO NEXT WEEK.
UPDATE
MOSTLY CLEAR SKIES AND FAIRLY MILD TEMPERATURES EXIST AROUND THE
REGION AT 1220Z. FOG WAS INTERMITTENTLY DENSE AT THE BAKER AIRPORT
DURING THE NIGHT, BUT RECENTLY THE FOG HAS DISSIPATED, AND THIS
IS CONFIRMED BY EARLY MORNING WEBCAMS. THERE IS LIKELY SOME
LOCALIZED SHALLOW VALLEY FOG, BUT HAVE CANCELLED THE DENSE FOG
ADVISORY FOR FALLON COUNTY. IT WILL BE DRY AND WARM TODAY WITH
TEMPS GETTING TO THE MID 70S TO MID 80S. JKL
DISCUSSION
NEXT 7 DAYS...
ON THE BACKSIDE OF THE LOW THAT GAVE US SCATTED SHOWERS
YESTERDAY, SOME AREAS OF FOG WILL DEVELOP THIS MORNING. THE MAIN
AREA FOR DEVELOPMENT WIS SE MONTANA INCLUDING MILES CITY AND
BAKER. SOME MODELS ARE MORE AGGRESSIVE WITH FOG DEVELOPMENT THAN
OTHERS, HOWEVER ALL SHOW BAKER BEING THE MAIN LOCATION FOR FOG
THIS MORNING. MODEL SOUNDINGS FROM NEARLY ALL SHORT RANGE MODELS
DEPICT A VERY GOOD FOG SETUP AT KBHK WITH THE SURFACE TEMPERATURE
DECREASING WELL BELOW THE CROSSOVER TEMPERATURE WITHIN THE NEXT
FEW HOURS. ADDITIONALLY LIGHT WINDS AND A VERY STRONG (10C)
INVERSION WILL AID IN FOG DEVELOPMENT. AS YOU PROGRESS FATHER WEST
AND SOUTHWEST THE CONDITIONS GRADUALLY BECOME LESS FAVORABLE. IN
SHORT, BAKER COULD SEE DENSE FOG THIS MORNING WITH MILES CITY
SEEING PATCHY FOG, SOME OF WHICH MAY BE DENSE IN RIVER VALLEYS.
TODAY, AND THROUGH MOST OF TOMORROW, WE WILL BE UNDER A BRIEF
PERIOD OF RIDGING. THIS WILL ALLOW FOR HIGHS TO REMAIN ABOVE
AVERAGE BOTH DAYS. LATE FRIDAY INTO EARLY SATURDAY, OUR NEXT
POTENTIAL WEATHER MAKER MOVES INTO THE REGION. THE WEAK LOW THAT
MOVES UP ALONG THE FRONT RANGE NOW LOOKS LIKE IT WILL MISS OUR CWA
JUST TO THE EAST AND THEREFORE, NOT GIVE US ANY PRECIP. THE GOOD
NEWS THOUGH IS THAT THIS VORT MAX WILL BE CLOSE ENOUGH TO HELP
FORCE THE SHORTWAVE MOVING IN OUT OF THE WEST JUST NORTH ENOUGH.
THIS SHOULD SPARE OUR CWA FROM A HIGH WIND EVENT. MODELS NOW SHOW
THE 50KT 700MB JET PASSING THROUGH NORTHERN MONTANA WITH THE
STRONGEST MODELED 700MB WINDS OVER SOUTH-CENTERAL MT ONLY
REACHING 30KTS. THESE WINDS ALOFT, AIDED BY A WEAK COLD FRONT,
WILL BE ENOUGH TO PRODUCE SOME BREEZY WINDS IN THE FOOTHILLS OF
OUR WESTERN CWA. THESE WINDS ARE NOT EXPECTED TO EXCEED 40MPH,
EVEN IN THE MOST GAP PRONE AREAS.
THE NEXT SHORTWAVE, PROGGED TO MOVE INTO OUR AREA LATE SUNDAY /
EARLY MONDAY, COULD BE A DIFFERENT STORY. MODELS ARE DEPICTING
THIS FEATURE AS A LONGWAVE TROUGH JUST OFF OF THE PACIFIC COAST
BEFORE SPLITTING INTO TWO DISTINCT AREAS OF ENERGY, ONE THAT
CONTINUES TO DIG INTO THE SW CONUS, AND ONE THAT MOVES THROUGH
OUR NECK OF THE WOODS. THIS IS WHY I REFER TO THIS FEATURE AS A
SHORTWAVE, BUT IT REALLY IS A DISJOINTED LONGWAVE TROUGH. ANYWAYS,
THE IMPACTS TO THE NORTHERN ROCKIES REGION WILL COME PRIMARILY IN
THE FORM OF PRECIPITATION. THIS SYSTEM WILL TAKE ADVANTAGE OF
BOTH THE SURFACE MOISTURE ADVECTING OUT OF THE PLAINS, AND THE
MOISTURE ALOFT IT DRAGS IN FROM THE PACIFIC. THIS COULD BRING
ANOTHER ROUND OF DECENT PRECIP AMOUNTS, ALTHOUGH NOT AS IMPRESSIVE
AS THE STORM SEVERAL DAYS AGO. THERE ARE ALSO HINTS THAT
ACCUMULATING SNOW OVER 9KFT COULD COME WITH THIS EVENT.
AS WE LOOK INTO LATE NEXT WEEK, THERE IS NO GOOD AGREEMENT
AMONGST MODELS AT ALL. WHAT THEY DO ALL SHOW THOUGH IS THAT WE
WILL START TO SEE DEEPER TROUGHS THAT MOVE THROUGH WESTERN NORTH
AMERICA. THESE COULD BE AIDED BY REMNANTS OF SEVERAL HURRICANES
CURRENTLY IN THE EAST PACIFIC AND THOSE THAT WILL LIKELY DEVELOP
SOON. SIMPLY, IT IS TOO EARLY TO SAY WITH ANY CONFIDENCE WHAT
WILL HAPPEN. IT DOES APPEAR THOUGH THAT THE NORTHERN HEMISPHERE
POLAR JET IS STARTING TO TAKE ON MORE "FALL- LIKE"
CHARACTERISTICS. WMR
AVIATION
12Z DISCUSSION.
VFR WILL PREVAIL OVER THE NEXT 24 HOURS UNDER HIGH PRESSURE ALOFT.
LOCALIZED EARLY MORNING SHALLOW FOG IN FAR SOUTHEAST MT WILL
DISSIPATE BY ~15Z. JKL
PRELIMINARY POINT TEMP/POPS
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 080 053/082 054/069 048/063 049/060 046/064 047/066
0/U 00/B 00/U 02/W 46/W 31/B 11/U
LVM 081 046/083 047/071 043/066 042/062 038/065 039/067
0/U 00/B 00/U 13/W 65/T 21/U 11/U
HDN 083 049/084 050/072 045/067 047/061 043/064 043/067
0/U 00/B 00/U 02/W 45/W 22/W 11/U
MLS 081 056/082 056/071 049/068 051/061 046/063 046/065
0/U 00/B 00/U 02/W 65/W 21/B 11/U
4BQ 079 053/081 056/072 050/072 052/062 047/062 045/066
0/U 00/B 00/U 02/W 66/W 42/W 11/U
BHK 082 050/079 052/074 046/070 049/062 042/061 042/064
0/F 00/N 00/U 12/T 76/T 21/B 11/U
SHR 080 046/082 050/073 045/068 046/058 041/061 039/064
0/U 00/B 00/U 02/W 38/T 63/W 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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